Alien seaweed threatens reefs

Infestations of an alien species of limu, or seaweed, threaten Hawaii’s coral reefs, said UH botanist Dr. Cindy Hunter. Gracilaria salicornia was intentionally introduced to the islands in an attempt at aquaculture, she said, but has now become a menace to native reefs.

Hunter said one solution to the alien algae problem is to physically remove it from the reef by hand. Several Waikiki Alien Algae Clean-Up events have been held in the past, resulting in a total of about 22.5 tons of the invasive limu being removed from Waikiki’s waters so far. She then announced the the next Waikiki alien algae cleanup event, scheduled for May 17.

The cleanup will take place on the War Natatorium side of the Waikiki Aquarium, and will involve scuba divers who pluck the algae off the seafloor, filling bags. The bags are then brought to shore, where the algae is weighed, sorted for native species and then the invasive species taken away for possible use as mulch.

Hunter spoke at the aquarium Thursday night along with UH emerita botanist Dr. Isabella Abbott in the third lecture of the Wakea and Papa (Heaven and Earth) Resource Connections in Waikiki series, sponsored by the Waikiki Aquarium and the Ali Wai Watershed Association.

Abbott opened her presentation by describing the importance of limu to ancient Hawaiian as a food source. She also described its cultural significance. Women were traditionally the limu gatherers, and so they also became the taxonomists, naming and differentiating between limu types and uses, she said.

The final lecture in the 2003 Natural History series at the Waikiki aquarium will take place on May 1 at 6 pm. The title of the talk will be Heavenly Connections- Climate, Weather, Seasons. The aquarium is located at 2777 Kalakaua Ave.. For more information, contact the Waikiki Aquarium Education Department at 923-9741, ext. 8-107.

Related Website:

Alien and Invasive Algae in Hawaii
2000 Coral Reef Initiative Research Program
Presented by Jennifer Smith